Microetching agent for copper, copper surface roughening method and wiring board production method

Abstract

A microetching agent is an acidic aqueous solution containing an organic acid, cupric ions, and halide ions. The molar concentration of halide ion of the microetching agent is 0.005 to 0.1 mol/L. By bringing the microetching agent into contact with a copper surface, the copper surface is roughened. An average etching amount in the depth direction during roughening is preferably 0.4 μm or less. The microetching agent can impart on copper surfaces a roughened shape having excellent adhesiveness to resins and the like, even with a low etching amount.

The invention claimed is: 
     
       1. A microetching agent for roughening a copper surface, wherein:
 the microetching agent is an acidic aqueous solution having a pH of more than 1 and 5 or less, 
 the microetching agent comprises an organic acid, cupric ions and chloride ions, 
 the microetching agent is free from a cupric complex of azoles, 
 the microetching agent is substantially free from a cationic polymer having a weight average molecular weight of 1000 or more, wherein a weight concentration of the cationic polymer is 0.5 ppm or less, 
 a molar concentration of the chloride ions is 0.005 to 0.1 mol/L, and 
 a molar concentration of the cupric ions is 2.2 to 30 times the molar concentration of the chloride ions. 
 
     
     
       2. The microetching agent according to  claim 1 , wherein a molar concentration of the cupric ions is 0.05 to 2 mol/L.